The present invention relates to a perforating-printing device using thermal stencils which is used for thermally perforating thernal stencils in accordance with originals as well as for producing printed copies by employing the perforated thermal stencils.
Thermal stencil duplication which employs thermally perforable stencil sheets for producing printed copies of originals is now widely employed as a means of duplication. As well known in the art, a thermal stencil sheet includes a thermally perforable thin plastic film which is made into a perforated stencil sheet having perforations corresponding to black portions of the original. In performing thermal stencil duplication, a thermal stencil sheet is pressed tightly onto an original which has characters and/or drawings inscribed thereon in a black material such as black ink which absorbs infrared rays. Then radiation including infrared rays is projected onto the original through the thermal stencil sheet, whereby the heat generated by infrared absorption in the black portions of the original melts away the corresponding portions of the thermoplastic film of the stencil sheet so as to produce a perforated stencil sheet. The perforated stencil sheet is then placed over an object which is to be printed, such as a sheet of paper, and printing ink is supplied onto the stencil sheet by means of an inking roller or the like thereby producing a copy printed with patterns corresponding to the perforated portions of the stencil sheet.
As an improvement of such a conventional method of producing printed copies by employing a stencil sheet and an inking roller or the like, it has been proposed in Japanese patent Application No. 30474/75 (Japanese Laying-Open Publication No. 104907/75) to employ a relatively viscous ink having substantially higher viscosity than conventional stencil printing ink in such a manner that the relatively viscous ink is supplied onto a stencil sheet in a relatively thick layer, thereby enabling the stencil sheet to produce a large number of printed copies by repeatedly being pressed onto the copy sheets, without receiving any subsequent supply of printing ink.
Following the invention of the aforementioned new method of stencil printing, a printing device suitable for use with the new printing method has been proposed in Japanese Utility Model Application No. 94408/75 (Japanese Utility Model Laying-Open Publication No. 9504/77). However, this is only a printing device, and for the perforating process of a thermal stencil, a conventional device for perforating thermal stencils is required.